Set a new default value for ``galera_wait_timeout`` which is inherited from global ``openstack_db_connection_recycle_time``.
These variables are directly related, it would cause errors when ``galera_wait_timeout`` is lower than ``openstack_db_connection_recycle_time``.
From the other hand, I don't see any reason for ``galera_wait_timeout`` to be higher than ``openstack_db_connection_recycle_time`` in most cases.
Change-Id: I9450912ec7960a8ab713517532164cab52628b30
b79574382b